Speaking multiple languages could slow down brain ageing and help to prevent cognitive decline, a study of more than 80,000 people has found.
The work, published in Nature Aging on 10 November, suggests that people who are multilingual are half as likely to show signs of accelerated biological ageing as are those who speak just one language.
“We wanted to address one of the most persistent gaps in ageing research, which is if multilingualism can actually delay ageing,” says study co-author Agustín Ibáñez, a neuroscientist at the Adolfo Ibáñez University in Santiago, Chile. Previous research in this area has suggested that speaking multiple languages can improve cognitive functions such memory and attention, which boosts brain health as we get older. But many of these studies rely on small sample sizes and use unreliable methods of measuring ageing, which leads to results that are inconsistent and not generalizable.
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“The effects of multilingualism on ageing have always been controversial, but I don’t think there has been a study of this scale before, which seems to demonstrate them quite decisively,” says Christos Pliatsikas, a cognitive neuroscientist at the University of Reading, UK. The paper’s results could “bring a step change to the field”, he adds.
They might also “encourage people to go out and try to learn a second language, or keep that second language active”, says Susan Teubner-Rhodes, a cognitive psychologist at Auburn University in Alabama.
Long live linguists
The researchers used a computational approach to explore the link between multilingualism and healthy ageing in 86,000 healthy participants aged between 51 and 90 years across 27 European counties.
For each participant, they determined the biobehavioural age gap, the difference between their chronological age — the number of years they have been alive — and their ‘predicted’ age, which considers various physiological, lifestyle and socioeconomic factors, ranging from cardiometabolic health to education level. A high biobehavioural age gap can be a sign that someone is ageing particularly fast — or slowly.
The researchers compared participants’ biobehavioural age gaps with the number of languages they spoke. This part of the data was based on self-reporting and therefore didn’t account for the level of language proficiency.
The researchers found that people who spoke only one language were twice as likely to have a high biobehavioural age gap than were those who spoke two or more languages. This effect increased with number of extra languages spoken. “Just one additional language reduces the risk of accelerated ageing. But when you speak two or three this effect was larger,” says Ibáñez.
Such a large study “really strengthens the interpretation that multilingualism, rather than other factors, protects us during ageing”, says Teubner-Rhodes. “It was using a really large, geographically diverse sample and that allowed them to control for a number of confounders that are typically present in multilingualism research, like immigrant status and wealth.” Future research should include more diverse populations outside Europe, she adds.
The researchers hope that their findings will influence policymakers to encourage language learning in education.
This article is reproduced with permission and was first published on November 10, 2025.